Overview: The Relief valves are safety valves prevent equipment damage by relieving accidental over-pressurization of fluid systems. The relief valves protects instruments such as motors,...
A simple control system drawn in block diagram form looks like this: Information from the measuring device (e.g. transmitter) goes to the controller, then to...
Introduction In control theory, an on/off controller, also known as a hysteresis controller, is a feedback controller that switches abruptly between two states. These controllers...
PID (Proportional – Integral – Derivative ) Controller Proportional The proportional term makes the current error signal multiplied with a gain (Kp).The result will be...
Override It is sometimes necessary to limit a variable in order to maintain safe operation or protect process equipment. If this variable is a function...
Feedforward A Feedforward control system measures a disturbance in variable, predicts its effect on the process and applies corrective action. Given an exact model of...
Ratio Control In Ratio Control, the controlled variable is the ratio of two measured variables. Control is effected by adjusting one of the variables –...